Diaphragm cell actuator



March 21, 1939. E. BECKER DIAPHRAGM CELL ACTUATOR Filed Aug. 17. 1957 m m M a |||l|1| m mm P. U5 U MM m. n m, m

Inventor:

Patented Mar. 21,

DIAPHRAGM CELL ACTUATOR Ewald Becker, Berlin-Steglita, Germany, assignor to Askania-Werke A. G., a corporation oi Germany Application August 17, 1937, Serial No. 159,599 In Germany August 18, 1938 3 Claims. (CI. 137-1565) This invention relates to a diaphragm cell ac- Fig. 1 is a diagram showing the operation of tuator, more particularly to an actuator for opa flat diaphragm subjected to a pressure. crating measuring and control devices in response Fig. 2 is a sectional elevation of a diaphragm to changes of the air density. cell actuator in connection witha spring loaded Heretofore, as far as I am aware, it has been control valve. 5 the practice to employ in measuring-and control The curve of Fig. 1 illustrates the magnitude devices of the above referred to character a presof stroke of a flat diaphragm ll sealing a diasure responsive member in the form of the usual phragm chamber II and being acted upon by a metallic sylphon or bellows or a plurality of the pressure inside the chamber. The stroke of the conventional corrugated diaphragm cells. These diaphragm in the center is 8+3. When an out- In conventional pressure and density responsive ward force is applied to the diaphragm in the members I have found to be disadvantageous and direction of the arrow I2, for instance by means unsuitable for precision regulators. The sylphon of a spring loading a valve, the stroke of the or bellows, for example, does not respond cordiaphragm is reduced in the center by an amount rectly to temperature and pressure changes on s. From the foregoing it appears that 9. dia- 15 account of the strain imparted to the material phragm having a flat surface is very responsive when forming the sylphon. The diaphragm to outward forces on account of its little stillness. cells, on the other hand, usually do not expand It has therefore been the practice to impress a and contract correctly in response to density plurality of corrugations into the diaphragm wall changes due to the stiffness imparted to the cells thereby making the. diaphragm stiller. The 20 by the corrugations. Finally, both the syphon greatly increased stillness, however, is equally and a stack of diaphragm cells possess little radial disadvantageous as it decreases the stroke of the stiffness and have the tendency to wobble or diaphragm due to the spring action of the coroscillate when subjected to vibration. The latrugated metal.

ter quality makes the conventional element un- The improved diaphragm cell actuator is shown 5 suitable for regulators on board aircraft, for in Fig. 2 as consisting of six single cells I 3. The example. lowermost cell bears against a fixed support It To overcome the hereinbefore outlined disadwhile the uppermost cell is-provided with a presvantages I propose to form a diaphragm cell acsure plate i5 bearing against a valve stem I6 tuator of a plurality of superposed cells, each of a valve ll of conventional construction. The 30 cell being made of two shells in the form of a valve may be supplied with pressure fluid to an irustum or a truncated cone and provided with inlet port it and possesses two outlet ports IS a single annular and outwardly projecting corand II controlled by cylindrical valve members rugation. The cells are interconnected by metal- 2! and 22. The stem I6 is further provided with lically securing the corrugations of two adioina disc 23 receiving the one end of a spring 24 35 log cells with each other, such as by welding or which bears with its other end against a fixed soldering. The diaphragm cell actuator thus support 25. Each diaphragm cell is composed of obtained responds to air density changes with two shells 26 and 21 shaped in the form of a great accuracy. It is suitable for operating a vfl'ustum or truncated cone and pr vided with a 40 relay of a regulator, even under load, and resingle outwardly projected corrugation 28 and 29. 40 mains unefiected by vibration on account of its The shells 2i and 21 are tightly connected at great stillness in radial direction. The diathe rim in a conventional manner, such as by phragm cell actuator moreover possesses a relawelding or soldering. Two adjoining cells are tively small size as compared to a stack of cells also metal cal v interconnected at 30 by we d interconnected by stubs or the like. I or soldering. It is, easily apparent from the 5 The object, aims and advantages of this indrawing that the diaphragm cell actuator will vention will become clear from a consideration be very l m n radial direction n not p n of this description together with the accompanyto vibrations imparting a radial force to the acing drawing in which an embodiment of my intuator as indicated by the arrow ll.

Y vention is shown for purely illustrative purpose. Referring again to Fig. 1, it is seen that the 50 It is to be understood, however. that the deloss of stroke by interconnecting the cells at the scription is not to be taken in a limiting sense. corrugation instead of at t e center is relatively the scope of this invention being defined in the small and may also be expressed as the amount appended claims. s in an unloaded condition. Experiments have Referring to the drawing: shown that an outward force, such as exerted by 55 a spring, used for loading a valve, will practically not reduce the stroke of a cell having a single corrugation and that the actuator will correctly respond to the changes in air pressure or air density..

As it is well known in the art a pressure responsive diaphragm cell isevacuated while a density responsive cell contains a charge of'gas.

Besides possessing the feature of inciosing a small volume relatively to a large surface, the

frustum-shaped shells ofler the advantage of being proof against excessive load. When acted upon by an overload, the walls oi the cell simply contact without causing deformation or damage to the cell.

What is claimed is:

1. Diaphragm cell actuator comprising a pinrality oi superposed cells of thin flexible sheet metal each of said cells being tightly sealed,

each cell wall having an annular outwardly projecting corrugation, said corrugation being metal- I I lically secured to the respective corrugation of V the adjoining cell.

2. Diaphragm cell actuator comprising a plurality of superposed cells of thin flexible sheet metal each of said cells being tightly sealed, consisting of two frustum-shaped shells tightly connected at the rim and provided each'with a single outwardly projecting annular corrugation, said corrugations being-metallically secured to the respective corrugation of the adjoining cell. 3. Diaphragm cell actuator comprising a plurality of superposed cells of thin flexible sheet metal, each of said cells being tightly sealed and consisting of two shells tightly connected at the rim and provided each with a single outwardly projecting annular corrugation, said corrugation being'metallically secured to the respective corrugation of the adjoining'cell.

EWALD BECKER. 20 

